Problem: Nadia ate 4 slices of pie. Stephanie ate 1 slice. If Nadia ate $\dfrac{4}{10}$ of the pie, what fraction of the pie was eaten?
Explanation: If 4 slices represent $\dfrac{4}{10}$ of the pie, there must have been a total of 10 slices. $\text{fraction of pie eaten} = \dfrac{\text{number of slices eaten}}{\text{number of slices total}}$ They ate ${5}$ out of $10$ slices. They ate $\dfrac{5}{10}$ of the pie.